Capacitive thin film pressure sensor

Abstract

The application provides a capacitive thin film pressure sensor and relates to the technical field of pressure sensors.The capacitive thin film pressure sensor comprises a shell, a nonmetal fixed electrode, an electrode assembly and a nonmetal thin film.The nonmetal thin film is located on the side of the nonmetal fixed electrode facing the connecting port.The side of the nonmetal fixed electrode facing the connecting port is provided with a first metal connecting layer.The nonmetal thin film is connected with the nonmetal fixed electrode through the first metal connecting layer.The capacitive thin film pressure sensor provided by the embodiment of the application connects the nonmetal thin film with the nonmetal fixed electrode through the first metal connecting layer.Because the nonmetal fixed electrode is insulated from the shell and the nonmetal thin film is not connected with the shell, the parasitic capacitance between the nonmetal fixed electrode and the shell is reduced, and the influence of the external environment on the measurement accuracy of the capacitive thin film pressure sensor is reduced.

Description

Technical Field

[0001] This invention relates to the field of pressure sensor technology, and more particularly to a capacitive thin-film pressure sensor. Background Technology

[0002] Existing capacitive film pressure sensors are categorized into metal capacitive film pressure sensors and non-metal capacitive film pressure sensors based on the type of film used. A typical metal capacitive film pressure sensor's core sensing element consists of five parts: a lower metal housing, an upper metal housing, a metal film fixed between the upper and lower metal housings, a fixed electrode plate with multiple electrodes arranged on the upper housing, and pins leading out the electrodes. Two ring capacitors are formed between the metal film and the fixed electrode plate. The metal film is connected to the outer shell and led out, while the ring electrodes are led out by the pins. The metal film divides the outer shell into two chambers. When the pressure in the two chambers is inconsistent, the pressure difference causes the film to deform, resulting in a change in capacitance, which is then output as a voltage and measured.

[0003] In existing technologies, parasitic capacitance is inevitably generated between the fixed electrode and the entire housing. When the external environment changes, the dielectric between the capacitors changes, causing a change in the dielectric constant of the capacitors, which in turn leads to inconsistent changes in the parasitic capacitance between the capacitors. This parasitic capacitance causes fluctuations in the measured capacitance value, reducing the measurement accuracy of the capacitive thin-film pressure sensor. Summary of the Invention

[0004] This invention provides a capacitive film pressure sensor to solve the technical problem that parasitic capacitance reduces the measurement accuracy of capacitive film pressure sensors.

[0005] This invention provides a capacitive thin-film pressure sensor, comprising:

[0006] The shell has an internal cavity, and the shell has a connection port communicating with the cavity;

[0007] A non-metallic fixed electrode is disposed within the cavity and connected to the housing;

[0008] Electrode assembly, disposed on the non-metallic fixed electrode;

[0009] A non-metallic thin film is located on the side of the non-metallic fixed electrode facing the connection port. A first metal connection layer is disposed on the side of the non-metallic fixed electrode facing the connection port. The non-metallic thin film is connected to the non-metallic fixed electrode through the first metal connection layer. The non-metallic thin film divides the cavity into a reference cavity and a process cavity. The reference cavity is located on the side of the non-metallic thin film away from the connection port, and the process cavity is located on the side of the non-metallic thin film facing the connection port. A metal layer is disposed on the side of the non-metallic thin film facing the non-metallic fixed electrode. The metal layer is electrically connected to the electrode assembly through the first metal connection layer.

[0010] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the electrode assembly includes at least two electrodes and at least two terminals. The electrodes are disposed on the non-metallic fixed electrode, and the terminals are disposed on the housing. The terminals are electrically connected to the electrodes in a one-to-one correspondence, and one of the electrodes is electrically connected to the first metal connection layer.

[0011] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the electrode includes two sub-electrodes, the two sub-electrodes of each electrode are respectively disposed on both sides of a non-metallic fixed electrode, the non-metallic fixed electrode is provided with at least two through holes, and the two sub-electrodes of each electrode are electrically connected through connectors in corresponding through holes; the terminal is located on the side of the non-metallic fixed electrode away from the connection port, and the terminal is electrically connected to the sub-electrodes on the side of the non-metallic fixed electrode away from the connection port in a one-to-one correspondence.

[0012] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the connector is a metal conductive layer disposed on the inner wall of a through hole.

[0013] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the terminal is sealed to the housing, and there is no electrical connection between the terminal and the housing.

[0014] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the electrode assembly includes a first electrode, a second electrode, a third electrode, and three terminals. The third electrode, located on the side of the non-metallic fixed electrode facing the connection port, is electrically connected to the first metallic connection layer. The first electrode, the second electrode, and the third electrode, located on the side of the non-metallic fixed electrode away from the connection port, are electrically connected to the three terminals one-to-one.

[0015] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the inner wall of the housing is provided with a connecting portion, and the non-metallic fixed electrode is connected to the connecting portion through a connecting layer.

[0016] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the connecting layer is sealed and fitted with the connecting portion and the non-metallic fixed electrode respectively.

[0017] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the first metal connection layer is sealed and fitted with the non-metallic fixed electrode and the non-metallic thin film respectively.

[0018] According to an embodiment of the present invention, a capacitive thin-film pressure sensor is provided, wherein the non-metallic fixed electrode and the non-metallic thin film are both made of quartz, and the housing is made of metal.

[0019] The capacitive film pressure sensor provided in this embodiment of the invention connects a non-metallic film to a non-metallic fixed electrode via a first metallic connecting layer. Since the non-metallic fixed electrode is insulated from the housing, and the non-metallic film is not connected to the housing, the parasitic capacitance between the non-metallic fixed electrode and the housing is reduced, thus reducing the influence of the external environment on the measurement accuracy of the capacitive film pressure sensor. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the front cross-sectional structure of the capacitive thin film pressure sensor provided in an embodiment of the present invention;

[0022] Figure 2 This is a bottom view schematic diagram of the non-metallic fixed electrode provided in an embodiment of the present invention;

[0023] Figure 3 This is a top view schematic diagram of the non-metallic fixed electrode provided in an embodiment of the present invention.

[0024] Figure label:

[0025] 100, Housing; 200, Non-metallic fixed electrode; 300, Electrode assembly; 310, Electrode; 311, First electrode; 311A, First sub-electrode; 311B, Second sub-electrode; 312, Second electrode; 312A, Third sub-electrode; 312B, Fourth sub-electrode; 313, Third electrode; 313A, Fifth sub-electrode; 313B, Sixth sub-electrode; 314, Connector; 320, Terminal; 400, Non-metallic thin film; 410, Metal layer; 500, First metal connection layer; 600, Connection layer; 700, Reference cavity; 800, Process cavity. Detailed Implementation

[0026] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0029] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0031] The following is combined with Figures 1-3 This invention describes a capacitive thin-film pressure sensor according to an embodiment of the present invention.

[0032] Figure 1 A schematic diagram of the front cross-sectional structure of the capacitive thin-film pressure sensor provided in an embodiment of the present invention is illustrated. Figure 1 As shown, the capacitive thin-film pressure sensor provided in this embodiment of the invention includes a housing 100, a non-metallic fixed electrode 200, an electrode assembly 300, and a non-metallic thin film 400. A cavity is formed inside the housing 100, and a connection port communicating with the cavity is formed in the housing 100. The non-metallic fixed electrode 200 is disposed within the cavity and connected to the housing 100. The electrode assembly 300 is disposed on the non-metallic fixed electrode 200. The non-metallic thin film 400 is located on the side of the non-metallic fixed electrode 200 facing the connection port. A first metal connection layer 500 is disposed on the side of the non-metallic fixed electrode 200 facing the connection port. The non-metallic thin film 400 is connected to the non-metallic fixed electrode 200 through the first metal connection layer 500. The non-metallic thin film 400 divides the cavity into a reference cavity 700 and a process cavity 800. The reference cavity 700 is located on the side of the non-metallic thin film 400 away from the connection port, and the process cavity 800 is located on the side of the non-metallic thin film 400 facing the connection port. A metal layer 410 is provided on the side of the non-metallic thin film 400 facing the non-metallic fixed electrode 200. The metal layer 410 is electrically connected to the electrode assembly 300 through the first metal connection layer 500, that is, the metal layer 410 is conductive to the electrode assembly 300 through the first metal connection layer 500.

[0033] The capacitive film pressure sensor provided in this embodiment of the invention connects the non-metallic film 400 to the non-metallic fixed electrode 200 through a first metal connecting layer 500. Since the non-metallic fixed electrode 200 is insulated from the housing 100, and the non-metallic film 400 is not connected to the housing 100, the parasitic capacitance between the non-metallic fixed electrode 200 and the housing 100 is reduced, and the measurement accuracy of the capacitive film pressure sensor is less affected by the external environment.

[0034] In an embodiment of the present invention, the first metal connecting layer 500 is sealed to the side of the non-metallic fixed electrode 200 facing the connection port, and the first metal connecting layer 500 is sealed to the edge of the non-metallic thin film 400. When the non-metallic thin film 400 is circular, the first metal connecting layer 500 is correspondingly annular.

[0035] In an embodiment of the present invention, the electrode assembly 300 includes at least two electrodes 310 and at least two terminals 320. Electrodes 310 are disposed on non-metallic fixed electrodes 200, and terminals 320 are disposed on the housing 100. Terminals 320 are electrically connected to electrodes 310 in a one-to-one correspondence, with one electrode 310 being electrically connected to a first metallic connection layer 500. Terminals 320 can be spring-pressed onto electrodes 310, thereby introducing an electrical signal into the circuit.

[0036] In an embodiment of the present invention, electrode 310 includes two sub-electrodes. The two sub-electrodes of each electrode 310 are respectively disposed on both sides of the non-metallic fixed electrode 200. The non-metallic fixed electrode 200 is provided with at least two through holes. The two sub-electrodes of each electrode 310 are electrically connected through connectors 314 within corresponding through holes. Terminals 320 are located on the side of the non-metallic fixed electrode 200 opposite to the connection port, and terminals 320 are electrically connected one-to-one with the sub-electrodes on the side of the non-metallic fixed electrode 200 opposite to the connection port.

[0037] In an embodiment of the present invention, the connector 314 is a conductive metal layer disposed on the inner wall of the through hole. The conductive metal layer can be disposed on the inner wall of the through hole by electroplating or other methods. Of course, the connector 314 can also be a wire disposed on the inner wall of the through hole.

[0038] In an embodiment of the present invention, the terminal 320 is sealed to the housing 100, and there is no electrical connection between the terminal 320 and the housing 100. The terminal 320 may be a metal pin. The metal pin may be sealed to the housing 100 by means of insulating sintering.

[0039] In embodiments of the present invention, such as Figure 1As shown, the electrode assembly 300 includes a first electrode 311, a second electrode 312, a third electrode 313, and three terminals 320. A gap is formed between the second electrode 312 and the first electrode 311 and the third electrode 313, and each of the first electrode 311, second electrode 312, and third electrode 313 is not electrically connected to any other electrode. The third electrode 313, located on the side of the non-metallic fixed electrode 200 facing the connection port, is electrically connected to the first metallic connecting layer 500. The first electrode 311, second electrode 312, and third electrode 313, located on the side of the non-metallic fixed electrode 200 away from the connection port, are electrically connected to the three terminals 320 one-to-one. The third electrode 313 is a common electrode, and the non-metallic thin film 400 is electrically connected to the third electrode 313 through the first metallic connecting layer 500.

[0040] Figure 2 A bottom view of the non-metallic fixed electrode 200 provided in an embodiment of the present invention is shown. Figure 3 A top view of the non-metallic fixed electrode 200 provided in an embodiment of the present invention is illustrated. Figure 2 and Figure 3 As shown, for ease of understanding, the sub-electrode of the first electrode 311 located on the side of the non-metallic fixed electrode 200 facing the connection port is called the first sub-electrode 311A, and the sub-electrode of the first electrode 311 located on the side of the non-metallic fixed electrode 200 away from the connection port is called the second sub-electrode 311B. The sub-electrode of the second electrode 312 located on the side of the non-metallic fixed electrode 200 facing the connection port is called the third sub-electrode 312A, and the sub-electrode of the second electrode 312 located on the side of the non-metallic fixed electrode 200 away from the connection port is called the fourth sub-electrode 312B. The sub-electrode of the third electrode 313 located on the side of the non-metallic fixed electrode 200 facing the connection port is called the fifth sub-electrode 313A, and the sub-electrode of the third electrode 313 located on the side of the non-metallic fixed electrode 200 away from the connection port is called the sixth sub-electrode 313B. The non-metallic thin film 400 is electrically connected to the fifth sub-electrode 313A through the first metallic connecting layer 500.

[0041] like Figure 2 As shown, the first sub-electrode 311A ​​is circular, while the third sub-electrode 312A and the fifth sub-electrode 313A are annular. The first sub-electrode 311A ​​is located inside the third sub-electrode 312A, and the fifth sub-electrode 313A is located on the outer periphery of the third sub-electrode 312A. Figure 3 As shown, the second sub-electrode 311B, the fourth sub-electrode 312B, and the sixth sub-electrode 313B are arranged at intervals, and the second sub-electrode 311B, the fourth sub-electrode 312B, and the sixth sub-electrode 313B correspond one-to-one with the three terminals 320.

[0042] In an embodiment of the present invention, a connecting portion is provided on the inner wall of the housing 100, and the non-metallic fixed electrode 200 is connected to the connecting portion through a connecting layer 600. When the non-metallic fixed electrode 200 is circular, the connecting layer 600 is annular so that the connecting layer 600 is fixedly connected to the edge of the non-metallic fixed electrode 200. The thickness of the connecting layer 600 can be determined according to actual needs.

[0043] In an embodiment of the present invention, the connecting layer 600 is sealed and fitted with the connecting part and the non-metallic fixed electrode 200 respectively. The material of the connecting layer 600 can be metal or non-metal. In this embodiment, the material of the connecting layer 600 is metal.

[0044] In an embodiment of the present invention, the first metal connection layer 500 is sealed and fitted with the non-metallic fixed electrode 200 and the non-metallic thin film 400 respectively.

[0045] In the embodiments of the present invention, the non-metallic fixed electrode 200 and the non-metallic thin film 400 are both made of quartz, and the housing 100 is made of metal.

[0046] In embodiments of the present invention, such as Figure 1 As shown, the upper, middle, and lower metal parts can be welded together to form a sealed metal housing 100. Three metal pins are fixed to the upper metal part by insulating sintering, and the non-metallic fixed electrode 200 is sealed and fixed to the middle metal part through a connecting layer 600. The lower metal part serves as the measurement medium inlet, connecting to external equipment to introduce the process medium.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A capacitive thin-film pressure sensor, characterized in that, include: The shell has an internal cavity, and the shell has a connection port communicating with the cavity; A non-metallic fixed electrode is disposed within the cavity and connected to the housing; Electrode assembly, disposed on the non-metallic fixed electrode; A non-metallic thin film is located on the side of the non-metallic fixed electrode facing the connection port. A first metal connection layer is provided on the side of the non-metallic fixed electrode facing the connection port. The non-metallic thin film is connected to the non-metallic fixed electrode through the first metal connection layer. The non-metallic film divides the cavity into a reference cavity and a process cavity. The reference cavity is located on the side of the non-metallic film away from the connection port, and the process cavity is located on the side of the non-metallic film facing the connection port. A metal layer is provided on the side of the non-metallic thin film facing the non-metallic fixed electrode, and the metal layer is electrically connected to the electrode assembly through the first metal connection layer; The electrode assembly includes a first electrode, a second electrode, a third electrode, and three terminals; the first electrode is located on the side of the non-metallic fixed electrode facing the connection port, forming a first sub-electrode; the first electrode is located on the side of the non-metallic fixed electrode away from the connection port, forming a second sub-electrode; the second electrode is located on the side of the non-metallic fixed electrode facing the connection port, forming a third sub-electrode; the second electrode is located on the side of the non-metallic fixed electrode away from the connection port, forming a fourth sub-electrode; the third electrode is located on the side of the non-metallic fixed electrode facing the connection port, forming a fifth sub-electrode; the third electrode is located on the side of the non-metallic fixed electrode away from the connection port, forming a sixth sub-electrode. The third sub-electrode and the fifth sub-electrode are in a ring shape, the first sub-electrode is located inside the third sub-electrode, and the fifth sub-electrode is located on the outer periphery of the third sub-electrode; the second sub-electrode, the fourth sub-electrode, and the sixth sub-electrode correspond one-to-one with the three terminals, and the terminals are disposed in the housing and are not conductive with the housing.

2. The capacitive thin-film pressure sensor according to claim 1, characterized in that, The non-metallic fixed electrode is provided with at least two through holes. The first sub-electrode and the second sub-electrode of the first electrode are electrically connected through connectors in the corresponding through holes. The third sub-electrode and the fourth sub-electrode of the second electrode are electrically connected through connectors in the corresponding through holes. The fifth sub-electrode and the sixth sub-electrode of the third electrode are electrically connected through connectors in the corresponding through holes. The terminal is located on the side of the non-metallic fixed electrode away from the connection port.

3. The capacitive thin-film pressure sensor according to claim 2, characterized in that, The connector is a conductive metal layer disposed on the inner wall of the through hole.

4. The capacitive thin-film pressure sensor according to any one of claims 1 to 3, characterized in that, The terminal block is sealed to the housing.

5. The capacitive thin-film pressure sensor according to any one of claims 1 to 3, characterized in that, The third electrode, located on the side of the non-metallic fixed electrode facing the connection port, is electrically connected to the first metallic connection layer. The first electrode, the second electrode, and the third electrode, located on the side of the non-metallic fixed electrode away from the connection port, are electrically connected to the three terminals one by one.

6. The capacitive thin-film pressure sensor according to any one of claims 1 to 3, characterized in that, The inner wall of the housing is provided with a connecting part, and the non-metallic fixed electrode is connected to the connecting part through a connecting layer.

7. The capacitive thin-film pressure sensor according to claim 6, characterized in that, The connecting layer is sealed and fitted with the connecting part and the non-metallic fixed electrode respectively.

8. The capacitive thin-film pressure sensor according to any one of claims 1 to 3, characterized in that, The first metal connection layer is sealed and fitted with the non-metallic fixed electrode and the non-metallic thin film respectively.

9. The capacitive thin-film pressure sensor according to any one of claims 1 to 3, characterized in that, The non-metallic fixed electrode and the non-metallic thin film are both made of quartz, while the housing is made of metal.

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